UPDATE: 4:30 a.m. EST -- Two U.N. peacekeepers and a contractor were killed, and 20 others were injured in a mortar attack Saturday on a peacekeeping base in northern Mali, Olivier Salgado, a spokesman for the U.N. force in Mali, told CNN. There has been no claim of responsibility until now, he added.

UPDATE: 4:18 a.m. EST -- Three people were killed when gunmen launched a rocket attack on a U.N. peacekeeping base in Kidal, a town in northern Mali, Agence France-Presse reported, citing U.N. sources. It is unclear how many people were injured in the incident. The identity of the attackers also remains unknown.

Original story:

Unidentified gunmen on Saturday fired rockets at a United Nations peacekeeping base in the northern Mali town of Kidal, causing an unspecified number of causalities, Reuters reported.

“The attack happened at around 4 a.m. (11 p.m. EST). Four or five rockets landed inside the base. Quite a few people were wounded but it’s too early for a precise number,” Olivier Salgado, a spokesman for the U.N. force in Mali, told Reuters.

U.N. peacekeeping forces and French troops have struggled to stabilize the regions of northern Mali, which has seen a rise in violence linked to Islamic fighters since 2012.

The incident follows a hostage crisis at a luxury hotel in Mali’s capital Bamako last week, in which 20 people were killed. Three Islamist militant groups -- al Qaeda in the Islamic Maghreb (AQMI), its splinter group al Mourabitoun and Massina Liberation Front (MLF) -- reportedly claimed the attack on the Radisson Blu hotel.